Ever since I was a kid, I've wondered how they made the 20Q electronic game. In this game, which is it's on device, you think of an object, thing, or animal (e.g. a potato or a donkey), once you mentally choose your thing, the device goes through a series of questions such as:

• Is it larger than a loaf of bread?
• Is it found outdoors?
• Is it used for recreation?

For each of the questions you can answer yes, no, maybe, or unknown. The way I've always thought of it to work was with immense, nested conditionals (if statements). But, I don't think that would be very likely as it would be terribly difficult to understand while coding it.

I'm not looking for a discussion as SE doesn't allow it; I'm looking for concrete knowledge or solutions.